1. Field of the Invention
The present invention relates to a multiple image processing system which is capable of producing image data output from a plurality of different types of input devices, in the form of a hard copy. Examples of the different types of input devices are an image input terminal (IIT) for reading an image of an original document and producing digital image data of a preset gray level, personal computers (PCs), and facsimiles (FAX). More particularly, the present invention relates to a multiple image processing system which is operable in a normal quality mode and also in a high quality mode.
2. Discussion of the Prior Art
Recently, developments have been made in digital image recording systems in which any of the image data, as read by the IIT, prepared by the PC, or received by the FAX, may be handled by using a single image output terminal (IOT).
In a prior art system, shown in FIG. 6, a user interface (UI) 40 is constructed with either the combination of a monochromatic or color CRT, and hard buttons or soft buttons, or, the combination of a display device, for example, a liquid crystal display device, and a control panel. From the UI 40, a user enters and sets up copy jobs specifying, for example, the number of copies, magnification, paper size, and edits to be applied to the image data. In the digital image recording system shown in FIG. 6, the UI 40 is also used when the user selects the image data to be copied from the output image data of a PC 41, an IIT 43 and, a FAX 44. The contents of a copy job as prepared at the UI 40 are transferred to a control unit 45.
Several different input devices may be used in conjunction with the UI 40 and the IOT 46. For example, PC 41 may be provided with a keyboard as an input device, a pointing device, and a color CRT as an output device. Documents, figures, and tables may be formed by the PC 41. A bit mapping circuit 42 receives code data from the PC 41, and generates a bit map of the received code data.
Another input device, IIT 43, includes a line sensor constructed with a CCD, for example, a drive circuit for the line sensor, a scanner with an A/D converter for converting an analog video signal output from the line sensor into digital image data of a preset number of bits, for example, 8 bits, and an image processing system unit (IPS) for applying various corrections and edits to the image data output from the scanner.
Yet another input device, FAX 44, may receive code data through a telephone line, for example, code data as specified by the CCITT, and convert it into image data to be processed.
The IOT 46, connected to each of the input devices through control unit 45, is provided with a black developing unit. If necessary, a single color developing unit or a plurality of color developing units may be coupled to the image output device 46.
The control unit 45 executes copy jobs as prepared by the UI 40 and oversees the operations of the image recording system in a supervisory manner.
As shown, the image recording system illustrated in FIG. 6 includes the PC 41, the IIT 43, and the FAX 44, which are for generating digital image data. In use, the IOT 46 is shared by these units.
When a copy job, prepared at the UI 40, contains image data generated by the PC 41, the control unit 45 transfers the image data supplied from the PC 41, to the IOT 46. The data output from the PC 41, when it is bit map data, is directly applied to the IOT 46. When the data output from PC 41 is code data, it is applied to the bit mapping circuit 42 where it is converted into bit map data. The bit map data is then sent to the image output device 46.
When the copy job, prepared at the UI 40, is to copy and output the image data as read by the IPS, the control unit 45 receives the image data output from the IIT 43 and sends it to the IOT 46.
When the copy job is to copy and transmit the image data received by the FAX 44, the control unit 45 transfers the image data as output from the FAX 44 to the IOT 46. The FAX 44 decodes the received image data and converts it into bit map data.
In the conventional system shown in FIG. 6, the connection of the input devices to the IOT 46 is selective. When any of the input devices is coupled, access of the remaining input devices to the IOT 46 is rejected. Thus, the digital image recording system, shown in FIG. 6, is not operable in the multiple function mode in which a plurality of devices may concurrently run. Therefore, an input device to be used must be selected from those input devices coupled each time it is used. Accordingly, it is difficult to increase the speed of the image processing for recording purposes.
The copy mode, in which a plurality of original documents are copied in a preset page order, and a plurality of copies of each document is produced, is frequently used. This copy mode is called a recirculating document handler (RDH) mode.
To exercise the RDH mode in the conventional image recording system shown in FIG. 6, a single original document is read by the IIT 43 a predetermined number of times, for example, N times. Each time the original document is read, a copy paper is discharged into one of the different bins of a sorter of the IOT 46 as output from the system. This sequence of the operations is time-consuming.
Another problem associated with conventional copying is unacceptable copy quality when copying photographs and documents including a series of fine patterns. When an image on the original document is a photograph or a series fine patterns, the copy must be made with an increased number of gray levels and at a higher resolution as compared with a copy of normal character documents, in order to achieve acceptable copy quality. In a conventional image recording system, as shown in FIG. 6, the gray levels and the resolution are preset at fixed values. Therefore, when a photograph or a document with a series fine patterns is copied using the conventional image recording system, the resultant image has unsatisfactory image quality.